Cache method results using Django cache framework

gistfile1.py

def cache_method_results(object_id = None, timeout = METHOD_RESULTS_TIMEOUT,
        argument_processor = None):
    ''' Cache the method results in the local cache. The decorator receives an 
        object_id, that can be a name of a member, name of a getter (method 
        which does not receive any arguments other than self) or a lambda 
        function for generating the id of the instance. It can also be empty 
        in case of a singleton. 
    '''
    from django.core.cache import get_cache
    cache = get_cache('common.method_results')
    def wrap(function):
        def new_function(*args, **kwargs):
            assert args
            object = args[0]
            if not object_id:
                id = '_'
            elif isinstance(object_id, types.FunctionType):
                id = object_id(object)
            elif isinstance(object_id, basestring) and hasattr(object, object_id):
                id = getattr(object, object_id)
                if isinstance(id, types.MethodType):
                    id = id()
            else:
                id = object_id

            if len(args) == 1:
                argument = ''
            else:
                if argument_processor:
                    argument = argument_processor(*args, **kwargs)
                else:
                    assert not kwargs # must have a processor
                    argument = ('_'.join(map(str, args[1:]))).strip()

            key = '_%s_%s_%s_%s' % (object.__class__.__name__,
                    id, function.__name__, argument)

            if cache.has_key(key):
                return cache.get(key)
            else:
                result = function(*args)
                cache.set(key, result, timeout)
                return result
        return new_function
    return wrap